It might sound crazy but...asking around. I think there are a lot more people already quietly doing the best they can to help, if not with actual gun violence, then with the factors that contribute to it. 

In the article about Ceasefire, it mentions "community leaders" and it was a group of pastors who went to the White House to appeal for extra help with it. I remember in Pensacola years ago there was a pastor downtown (smack in the poorest neighborhoods) who was singlehandedly and voluntarily running a food pantry, mentoring the youth and providing them a haven to help keep them off the streets and out of trouble. If I recall correctly he was letting kids come to the church after school so they'd have a safe place to hang out and do homework till their parents got home. No fanfare, no outside assistance. That's the kind of person you want, just IMHO. 

I'm sure the local police in every community also know "who's who" and probably could point to the people who have influence, for good or bad. Ask them. 

And obviously not all community leaders are religious, but that's just an easy place to start. If you look at "Returning the Favor" run by Mike Rowe on facebook, he kicked off that whole show by first making a post asking people to nominate "do-gooders" and the response was overwhelming. I remember reading the comments on that "asking around" post and being simply amazed by what people will do for no other reason than out of the goodness of their hearts. Just in the last month he's featured a woman who is employing former convicts to keep them from recidivism, a woman who is helping street kids, and a man who runs a "bully rehab" effort that includes empowering victims. All groups of people with that "higher risk" of becoming a tragic statistic.